WhatsApp has notified around 200 Italian users who mistakenly installed a malicious fake version of its messaging app, which contained spyware. The company accused the Italian spyware maker SIO of creating this fake application for iPhones.

The notification process involved logging out the affected users and advising them to remove the unofficial client in favour of downloading the authentic WhatsApp app. Despite concerns over potential targets such as journalists or civil society members, no further details have been released by WhatsApp.

As part of its response, WhatsApp intends to file a legal demand against SIO to curb this malicious activity. This incident comes on the heels of last year’s revelations that SIO was behind several spyware-infested Android apps, including fake versions of other messaging services.

The use of such tactics by Italian authorities is not unprecedented, with reports indicating collaboration between law enforcement and cellphone providers in sending phishing links to customers. Apple has remained silent on the matter, while SIO did not respond to requests for comment.